1.
contrarian, perverse person, someone who does the opposite
A person who deliberately does or says the opposite of what others expect or want. Common trait in children going through rebellious phases.
あまのじゃくだね。
You're such a contrarian.
Kanji: Written as 天邪鬼 or 天の邪鬼.
Etymology: Originally a demon from Japanese folklore that could read minds and did the opposite of what people wanted. The name comes from Buddhist and Shinto mythology.
Usage: Can function as a noun or na-adjective (あまのじゃくな).
Nuance: Often used affectionately for children who are being deliberately contrary, or self-deprecatingly by adults who recognize this trait in themselves (especially in romantic contexts - people who act cold when they're actually interested).
Psychology: Sometimes describes tsundere-like behavior where someone expresses the opposite of their true feelings.